A conventional saddle device disclosed in U.S. Pat. No. 694,875 includes a bottom seat, a shaft rod mounted to the bottom seat, and two saddles threadedly connected to the shaft rod. Each of the saddles has a front end portion, and a rear end portion opposite to the front end portion, and disposed for mounting the shaft rod. Two ends of the shaft rod respectively have a right-handed thread section and a left-handed thread section. The saddles are respectively and threadedly connected to the right-handed thread section and the left-handed thread section of the shaft rod.
When the shaft rod rotates, the right-handed thread section and the left-handed thread section cooperate to drive a relative movement between the saddles for adjusting a distance between the saddles.
Even if the conventional saddle device can adjust the distance between the saddles, for most of bicycles, a portion of a bicycle for mounting the saddles is fixed such that, the positions of the saddles in a front-rear direction are not adjustable for different users.
In addition, the conventional saddle device disclosed in U.S. Pat. No. 694,875 does not include a backrest structure for supporting the back of a user. When the backrest structure is mounted to the conventional saddle device, supporting members are required to be disposed, and the complexity of the conventional saddle device will be increased.
Moreover, the user usually requires some repair tools and repair members for repairing the bicycle, and usually needs to bring a wallet, since the structure of the bicycle frame is simple, it is difficult to mount a bag on a bicycle frame near a saddle portion of the bicycle for receiving the repair tools, the repair members and the wallet, and the conventional saddle device disclosed in U.S. Pat. No. 694,875 does not include a coupling structure for mounting a saddle bag.